1. Field of the Invention
This invention pertains to gamut mapping methods. Specifically, the invention relates to gamut mapping methods using primary cusp points, lightness compression toward cusp point lightness, and chroma expansion, and further relates to the use of these techniques to enable simulation of saturation control in an appearance space that is generally lacking direct saturation control, through the manipulation of lightness and chroma.
2. Related Background Art
Gamut mapping is the procedure by which the colors from one device are rendered into the color space of another device. A common form of gamut mapping is performed when a source image, coming from a device having a large color gamut, is mapped to a reproduction device having a smaller color gamut.
The development of gamut-mapping algorithms (GMAs) has gathered much momentum in the last decade and certainly, much progress has been made. However, unless two devices are identical, there is always the possibility that a better mapping between the two can be found. In any case where the colors of a large gamut need to be rendered into the colors of a smaller gamut, decisions need to be made as to just exactly how this should be done. The decisions are not only based upon the two gamuts, but also on the images being mapped and the intent of the reproduction.
While many GMAs attempt to reproduce colors as accurately as possible, this type of conversion can result in dull colors being rendered into the destination gamut, which can produce unappealing results. This problem can be particularly noticeable when printing business graphics, for which a user may want to produce bright, vivid colors.